オルガネラ分子の化学的修飾法の開発

京都大学0048新制・課程博士博士(工学)甲第22015号工博第4627号新制||工||1721(附属図書館)京都大学大学院工学研究科合成・生物化学専攻(主査)教授 浜地 格, 教授 梅田 眞郷, 教授 跡見 晴幸学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDGA

Organelle membrane-specific chemical labeling and dynamic imaging in living cells

狙った細胞内小器官脂質の可視化に成功 --オートファゴソーム形成機構解明に貢献--. 京都大学プレスリリース. 2020-09-28.Lipids play crucial roles as structural elements, signaling molecules and material transporters in cells. However, the functions and dynamics of lipids within cells remain unclear because of a lack of methods to selectively label lipids in specific organelles and trace their movement by live-cell imaging. We describe here a technology for the selective labeling and fluorescence imaging (microscopic or nanoscopic) of phosphatidylcholine in target organelles. This approach involves the metabolic incorporation of azido-choline, followed by a spatially limited bioorthogonal reaction that enables the visualization and quantitative analysis of interorganelle lipid transport in live cells. More importantly, with live-cell imaging, we obtained direct evidence that the autophagosomal membrane originates from the endoplasmic reticulum. This method is simple and robust and is thus powerful for real-time tracing of interorganelle lipid trafficking

Rapid labelling and covalent inhibition of intracellular native proteins using ligand-directed N-acyl-N-alkyl sulfonamide

細胞内の狙った天然タンパク質を迅速に化学修飾する分子技術を開発 --不可逆阻害剤開発のための新しい戦略--. 京都大学プレスリリース. 2018-05-16.Selective modification of native proteins in live cells is one of the central challenges in recent chemical biology. As a unique bioorthogonal approach, ligand-directed chemistry recently emerged, but the slow kinetics limits its scope. Here we successfully overcome this obstacle using N-acyl-N-alkyl sulfonamide as a reactive group. Quantitative kinetic analyses reveal that ligand-directed N-acyl-N-alkyl sulfonamide chemistry allows for rapid modification of a lysine residue proximal to the ligand binding site of a target protein, with a rate constant of ~104 M−1 s−1, comparable to the fastest bioorthogonal chemistry. Despite some off-target reactions, this method can selectively label both intracellular and membrane-bound endogenous proteins. Moreover, the unique reactivity of N-acyl-N-alkyl sulfonamide enables the rational design of a lysine-targeted covalent inhibitor that shows durable suppression of the activity of Hsp90 in cancer cells. This work provides possibilities to extend the covalent inhibition approach that is currently being reassessed in drug discovery

A Set of Organelle-Localizable Reactive Molecules for Mitochondrial Chemical Proteomics in Living Cells and Brain Tissues

Protein functions are tightly regulated by their subcellular localization in live cells, and quantitative evaluation of dynamically altered proteomes in each organelle should provide valuable information. Here, we describe a novel method for organelle-focused chemical proteomics using spatially limited reactions. In this work, mitochondria-localizable reactive molecules (MRMs) were designed that penetrate biomembranes and spontaneously concentrate in mitochondria, where protein labeling is facilitated by the condensation effect. The combination of this selective labeling and liquid chromatography–mass spectrometry (LC–MS) based proteomics technology facilitated identification of mitochondrial proteomes and the profile of the intrinsic reactivity of amino acids tethered to proteins expressed in live cultured cells, primary neurons and brain slices. Furthermore, quantitative profiling of mitochondrial proteins whose expression levels change significantly during an oxidant-induced apoptotic process was performed by combination of this MRMs-based method with a standard quantitative MS technique (SILAC: stable isotope labeling by amino acids in cell culture). The use of a set of MRMs represents a powerful tool for chemical proteomics to elucidate mitochondria-associated biological events and diseases